CVE-2023-40165
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedrubygems.org is the Ruby community's primary gem (library) hosting service. Insufficient input validation allowed malicious actors to replace any uploaded gem version that had a platform, version number, or gem name matching `/-\d/`, permanently replacing the legitimate upload in the canonical gem storage bucket, and triggering an immediate CDN purge so that the malicious gem would be served immediately. The maintainers have checked all gems matching the `/-\d/` pattern and can confirm that no unexpected `.gem`s were found. As a result, we believe this vulnerability was _not_ exploited. The easiest way to ensure that a user's applications were not exploited by this vulnerability is to check that all of your downloaded .gems have a checksum that matches the checksum recorded in the RubyGems.org database. RubyGems contributor Maciej Mensfeld wrote a tool to automatically check that all downloaded .gem files match the checksums recorded in the RubyGems.org database. You can use it by running: `bundle add bundler-integrity` followed by `bundle exec bundler-integrity`. Neither this tool nor anything else can prove you were not exploited, but the can assist your investigation by quickly comparing RubyGems API-provided checksums with the checksums of files on your disk. The issue has been patched with improved input validation and the changes are live. No action is required on the part of the user. Users are advised to validate their local gems.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysisThe application accepts input without confirming it is well-formed or within expected bounds, so malformed data can push the program into states its author never anticipated. Attackers probe these gaps to trigger crashes, bypass logic, or feed tainted values into more dangerous operations downstream. Remediating it well means validating and normalising every input at the boundary against a strict allow-list — not merely filtering known-bad values.
General guidance for the improper input validation class — the official description and references above are authoritative for this specific CVE. Want a bespoke review and a reviewed fix? Ask our team →
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data< 2023-08-14CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- High
- Availability
- None
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
dbcve · scoped2023-08-14
- No user action required. The vulnerability was patched server-side by the RubyGems.org maintainers as of 2023-08-14.
- Optional: Verify the integrity of your downloaded gems by running `bundle add bundler-integrity` followed by `bundle exec bundler-integrity` to compare checksums from RubyGems.org API with local files.
Generated from the published advisory — verify against the referenced sources before acting.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2023-40165 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2023-40165 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
- No spam, self-promotion, credentials, or personal data